Method of establishing a connection between a calling subscriber of a telecommunications network and a called target subscriber of a mobile radio network
The invention relates to a method of establishing a connection between a calling subscriber of a telecommunications network and a called mobile target subscriber of a cellular digital mobile radio network.
The system description "D900--mobile communication system", system description SYD, 1992 (order number A30808-X3231-X-2-7618) discloses the structure of a digital cellular mobile radio network conforming to the GSM standard (global system for mobile communication) for the transmission of voice and data. The essential components of the mobile radio network are the base station system, the switching subsystem and the operating and maintenance subsystem. The base station system, comprising a radio part and a hardwired part, represents the interface with respect to the mobile stations of the mobile subscribers of the mobile radio network on the one hand and the interface with respect to the switching subsystem on the other hand, which is responsible for the classical switching functions, including the connections to other telecommunications networks, such as for example the public telephone network or another mobile radio network.
International Patent Application WO 92/10069 discloses a method and an arrangement for connecting a stationary subscriber to a neighboring mobile subscriber with the assistance of a switching system with connected data processing device in a line-connected telephone network. For forming a taxi call system without the intermediary of a telephonist or an operator, location information on the calling stationary subscriber and a plurality of mobile subscribers of a group dialled by a group call number are requested by the data processing device and subsequently evaluated. Thereupon, the taxi driver who is closest with respect to the calling stationary subscriber, who is not already blocked by a call and is free to take on the taxi service required is selected as the mobile subscriber. The selection of the mobile subscriber consequently takes place in the line-connected telephone network by a data processing system in combination with the switching system, which has lines coming in from the stationary subscribers and lines going out to the mobile subscribers. The lines going out from the switching system lead to a mobile radio network, in which a connection via a radio path is established in each case only for the one selected mobile subscriber.
A digital mobile radio network, which has a multiplicity of radio cells for the blanket coverage of the "roaming" mobile subscribers, may also sustain the structure of an intelligent network, which is characterized by decentralized intelligence distributed over the entire network in the individual items of network equipment. The mobile radio network with the structure of an intelligent network has service switching points, service control points and service management systems--see system description "D900 . . .", page 11, Section 2.3. In such a structured intelligent network, new services and supplementary services can be easily and flexibly introduced.
In the GSM mobile radio network, all the interfaces between the items of equipment are standardized. Services and supplementary services in conformity with the GSM standard are available to the mobile subscribers. Also non-standardized supplementary services may be set up, identified by corresponding service codes (supplementary services codes). One of these supplementary services is "mobile access hunting", the utilization of which is intended to have the effect of setting up a connection between a calling subscriber of a telecommunications network and a mobile target subscriber of the mobile radio network, selected from a target group of mobile subscribers. Such target groups are defined by specific groups of persons, such as for example service technicians or employees in field service, or by the type of services which can be used, such as for example taxi call services, private delivery services etc.